Apparatus for removing metallic particles from paper-pulp



(Nd Model.)

C. H. ATKINS.

APPARATUS FOR. REMOVING METALLIC PARTICLES FROM PAPER PULP.

Patented Nov. 27, 1888..

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UNITED STATES 7 Tries.

PATENT APPARATUS FOR REMOVING METALLIC PARTICLES FROM PAPER-PULP.

SPECIFICATION forming part of Letters Patent No. 393,348, dated November27, 1888.

Application filed July 16, 1837. Serial No. 244,468. (No model.)

To all 2075/0171, it may concern.-

Be it known that I, CHARLES H. ATKINS,Of Boston, in the county ofSuffolk and State of Massachusetts, a citizen of the United States, haveinvented a new and useful Improvement for Removing Metallic Particlesfrom Paper- Pulp,ofwhich the following is a full,clear,and exactdescription, reference being had to the accompanying drawings,forming apart ofthis specification in explaining its nature.

In the manufacture of paper it frequently happens that fine metallicparticles are carried along in the pulp to the wire cylinder of thepaper-machine, and form,eventually,an integral part of the paper,inwhich the presence of the metallic particlesis a commercial defect.These metallic particles are mostly either of brass or copper, or ofiron, the iron particles being derived from the abrasion of the ironparts of what are technically known as the engines, and thebronzeorcopper particles beingderived from some other parts of themachinery-such as bearings or from the vats and valves of water or steampipes. One class of these particlesnamely, those which are copper,bronze, lead, tin, and the like-are readily entangled and held bymercury; but mercury does not very readily attack, or at least veryreadily eat, hammer-hardened or rolled copper, particularly if suchrolled copper has the suboxide face which is usual on hot-worked copper.

My invention, therefore, consists in introducing between thepulp-engines and the vat from which the pulp is dipped by hand-sieve, orinto which it runs to be taken up by the cylinder of the ordinarypaper-machine,a trough in which the pulp in its passage from the en gineto the vat shall be exposed to magnetic and mercurial influences, andalso in the details of the construction of such trough and of itssurroundings and accessories.

The trough is made of sheet-copper, prefer- Y ably in a single piece,and slopes downward from the engine to the pulpvat. It may be of anyconvenient length. The slope of this copper trough is not a uniformslope; but it is provided with what are known in mining engineering asrifiles, or small dams which extend from side to side. These riftlesfurnish pans of the width of the trough for the reception of mercury,and between the ri'llles are placed magnets close up to the copper onthe trough. As the pulp flows down from the pulp-engine to the vat, itsflow will be alternately accelerated and retarded,and eonsequentlyin atraverse over a considerable number of riffles almost every particle ofthepulp (probably every particle of the pulp) will have come within themagnetic field of the magnets, and will have traversed the surface ofthe mercury in one of the mercurial receptacles.

In the drawings, Figure 1 shows, in elevation,at E, the pulp-vat. At Ais represented the bottom of the trough, of which B are thedepressions,which I have called riffles. O is the mercury contained inthese riflles. D represents the electro-magnets,placed between theriffles and close to the bottom surface of the trough. A portion of thetrough with its riffles and mercury and an adjacent magnet is shown inFig. 2.

Fig. 3 is a transverse section at the line at a; of Fig. 2, and showsthe trough with its sides F F. Only two magnet-s, placed at the centerof the trough, are represented in Fig. 3; but it is my intention toplace a series of magnets side by side across the whole width of thetrough, so that in the space between the riflles there shall be no partof the trough which is not under magnetic influence or within themagnetic field of some magnet.

The magnets which I employ are electro magnets, because with them greatmagnetic power can be obtained.

Vhen the mercury becomes too much saturated with the particles which itwill absorb and amalgamate, it is to be drawn off and distilled in theusual way, and when the delivery of pulp to the pulp-vat ceases for anyreason the surface of the trough is to be cleaned from particles held toit by the influence of the magnets.

I prefer to make a trough in a single piece without riveting, and Iprefer to mount the magnets on a movable slide, so that they can bewithdrawn during the process of cleaning the trough; but these thingsare not absolutely essential to the working of my invention. Any othermetal than copper, which is equally-insuseeptible to the influence ofmercury, will serve to make the trough; but I do not think that a troughmade of iron would. be as good p as a trough made of copper,becanse thewater of the pulp would be apt to rust the iron,and the iron would beapt to have residual magnetism which would render it difficult to clean.

5 It is for this reason that I recommend nonmagnetic sheet metal for thematerial of the trough.

Having thus fully described my invention, I claim and desire to secureby Letters Patent of the United States The improvement in apparatus forthe in anufacture of paper, comprising the pulp-vat of thepulping-engine and the pulp-vat from which the sieves remove the pulp insheets or r 5 layers, and a pulp-trough interposed between the saidpulp-vats having a sheet-copper bottom along which the pulp is caused toflow, which copper bottom is wrought with ril'fles containing mercury intheir cavities, and a series of electro-magnets below said copper 20bottom, the magnetic fields whereof extend across said trough from sideto side, whereby the particles of magnetic metal and of metal capable ofamalgamation in the pulp are detained on or near the bottom of thepulp-trough, 2 5 substantially as and for the purposes described.

CHARLES H. ATKINS. Vitnesses:

Trros. WM. CLARKE, WILBUR D. FISKE.

